IVGCVSW-2371 Add Rsqrt Ref implementation

*Added Unit Tests

Change-Id: I6cceb8e6dcda35ce08415f8e5ca86019a64d26e3
diff --git a/src/backends/reference/workloads/RefWorkloads.hpp b/src/backends/reference/workloads/RefWorkloads.hpp
index ddce68e..8beb03f 100644
--- a/src/backends/reference/workloads/RefWorkloads.hpp
+++ b/src/backends/reference/workloads/RefWorkloads.hpp
@@ -59,3 +59,4 @@
 #include "RefBatchToSpaceNdUint8Workload.hpp"
 #include "RefBatchToSpaceNdFloat32Workload.hpp"
 #include "RefDebugWorkload.hpp"
+#include "RefRsqrtFloat32Workload.hpp"